Hostname: page-component-745bb68f8f-mzp66 Total loading time: 0 Render date: 2025-01-27T02:37:16.144Z Has data issue: false hasContentIssue false
  • English
  • Français

Stochastic System Identification of the Compliance of Conducting Polymers

Published online by Cambridge University Press:  01 February 2011

Priam Vasudevan Pillai  and
Ian W. Hunter
Priam Vasudevan Pillai
Affiliation:
[email protected]@mit.edu, Massachusetts Institute of Technology, Mechanical Engineering, United States
Ian W. Hunter
Affiliation:
[email protected], Massachusetts Institute of Technology, Mechanical Engineering, United States
Get access

Abstract

Conducting polymers such as polypyrrole, polythiophene and polyaniline are currently studied as novel biologically inspired actuators. The actuation mechanism of these materials depends upon the motion of ions in and out of the polymer film during electrochemical cycling. The diffusion of ions into the bulk of the film causes the dynamic mechanical compliance (or modulus) of the material to change during the actuation process. The mechanism of this change in compliance is not fully understood as it can depend on many different factors such as oxidation state, solvation of the film and the level of counter ion swelling. In-situ measurement of the dynamic compliance of polypyrrole as a function of charge is difficult since the compliance depends upon the excitation frequency as well as the electrochemical stimulus. Pytel et al [1] studied the effect of the changing elastic modulus in-situ at a fixed frequency. In this study we describe a technique to measure the compliance response of polypyrrole as a function of frequency and electrochemistry. A voltage input and a simultaneous stress input was applied to polypyrrole actuated in neat 1-butyl-3-methylimidazolium hexaflourophosphate. The stress input was a stochastic force with a bandwidth of 30 Hz and it allows us to compute the mechanical compliance transfer function of polypyrrole as function of the electrochemistry. Our studies show that the low frequency compliance changes by 50% as charge was injected into the polymer. The compliance changes reversibly as ions diffuse in and out of the film which indicates that the compliance depends upon the level of counter ion swelling.

Keywords

polymerbiomimetic (assembly)elastic properties
Type
Research Article
Information
MRS Online Proceedings Library (OPL) , Volume 1134: Symposium BB – Polymer-Based Smart Materials–Processes, Properties and Application , 2008 , 1134-BB07-03
Copyright
Copyright © Materials Research Society 2009

Access options

Get access to the full version of this content by using one of the access options below. (Log in options will check for institutional or personal access. Content may require purchase if you do not have access.)

References

REFERENCES

1. Pytel, R.Z., Thomas, E.L, and Hunter, I. W., Polymer. 49, 2008–2013, (2008).Google Scholar
2. Cohen, Y.B., “Electroactive Polymer [EAP] Actuators as Artificial Muscles- reality, potential and challenges” ed Cohen, Y. B. SPIE press (2001)Google Scholar
3. Spinks, GM, Liu, L, Wallace, GG, and Zhou, DZ. Advanced Functional Materials 12 (6–7):437–440 (2002)Google Scholar
4. Bay, L, Mogensen, N, Skaarup, S, Sommer-Larsen, P, Jorgensen, M, and West, K. Macromolecules, 35(25):9345–9351 (2002).Google Scholar
5. Otero, TF, Lopez Cascales, JJ, and Vazquez Arenas, G. Materials Science and Engineering: C 27(1):18–22 (2007)Google Scholar
6. Samani, MB, Cook, DC, Madden, JD, Spinks, G, and Whitten, P. Thin Solid Films, 516:2800–2807 (2007)Google Scholar
7. Vandesteeg, N. PhD. Thesis. Synthesis and Characterization of Conducting Polymer Actuators. Materials Science and Engineering, Massachusetts Institute of Technology, (2007)Google Scholar
8. Juang, Jer Nan. “Applied System Identification”. Englewood Cliffs, NJ: Prentice Hall; 1994.Google Scholar
9. Vandesteeg, N, Anquetil, P, and Poly, Hunter I. (3, 4-ethylenedioxythiophene) actuators: the role of cation and anion choice. SPIE Smart Structures and Materials 2004: Electroactive Polymers Actuators and Devices. San Diego, CA, 2004 Google Scholar
10. Ding, J, Zhou, DZ, Spinks, G, Wallace, G, Forsyth, S, Forsyth, M, and MacFarlane, D. Chemistry of Materials, 15(12):2392–2398 (2003)Google Scholar
11. Eykhoff, Pieter. “System Identification: Parameter and State Estimation”. John Wiley & Sons; (1974)Google Scholar